1. Field of the Invention
This invention relates to a method of fabrication of semiconductor devices, and more particularly to a simplified method of making V-groove junction field effect transistor devices.
2. Description of the Prior Art
The economical manufacture of semiconductor transistor devices using present-day techniques is directly related to the number of masking steps required during the manufacturing process, and to the number of transistor devices that may be formed on each wafer. With respect to the making of V-groove junction field effect transistors (VJ-FET's) in particular, the prior art discloses the need to use at least three masking steps (and often four with passivation) during the manufacturing process. As the number of masking steps increases, the ultimate yield of working devices decreases and the total processing time increases. Further, the more masks required during fabrication, the fewer transistor devices that can be manufactured on a wafer because of the cumulative mask alignment tolerances incurred. It is therefore economically advantageous to be able to manufacture VJ-FET devices with fewer than three masks, while retaining the desirable electrical and physical characteristics of the overall VJ-FET device structure.
Accordingly, it is an object of the present invention to provide a very simple method of producing VJ-FET devices utilizing only two photolithographic masking steps.
It is a further object of the present invention to provide a simplified method for increasing the yield and density of VJ-FET devices on a semiconductor wafer.
This and other objects of the present invention are achieved by a VJ-FET device fabrication method using only two photolithographic masking steps, wherein preferential etching of the semiconductor wafer material results in a V-shaped groove between the source and drain regions with the device channel passing around the V-groove. Also disclosed are V-shaped isolation grooves surrounding the active regions of a VJ-FET and formed concurrently with the V-groove separating the source and drain regions.